a=[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
def T(a):
    b=[]
    for i in range(len(a[0])):
        b.append([])
    for i in range(len(a)):
        one=a[i]
        for j in range(len(one)):#cell in one:
            b[j].append(one[j])
    return b
if __name__=="__main__":
    print(T(a))

